/*
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package cn.com.dhc.danlu.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Typeface;
import android.os.Build;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.HorizontalScrollView;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.Locale;

import cn.com.dhc.danlu.R;

/**
 * 滑动指示器pstsindicatorcolor颜色
 * 在视图的底部的全宽度的线pstsunderlinecolor颜色
 * 选项卡之间的分隔pstsdividercolor颜色
 * 滑动指示器pstsindicatorheightheight
 * 在视图的底部的全宽度的线pstsunderlineheight高度
 * pstsdividerpadding顶部和底部填充的分频器
 * pststabpaddingleftright左、右填充每个选项卡
 * pstsscrolloffset卷轴被选择的标签的偏移
 * pststabbackground背景绘制的每个标签，应该是一个statelistdrawable
 * pstsshouldexpand如果设置为TRUE，每个标签都给予同样的重量，默认为false
 * pststextallcaps如果为真，所有选项卡标题都是大写，默认为true
 */
public class PagerSlidingTabStrip extends HorizontalScrollView {

    // @formatter:off
    private static final int[] ATTRS = new int[] {
            android.R.attr.textSize,
            android.R.attr.textColor
    };
    private final PageListener pageListener = new PageListener ();
    // @formatter:on
    public OnPageChangeListener delegatePageListener;
    private LinearLayout.LayoutParams defaultTabLayoutParams;
    private LinearLayout.LayoutParams expandedTabLayoutParams;
    private LinearLayout tabsContainer;
    private ViewPager pager;
    private int tabCount;
    private int currentPosition = 0;
    private int selectedPosition = 0;
    private float currentPositionOffset = 0f;
    private Paint rectPaint;
    private Paint dividerPaint;
    private int indicatorColor = 0xFF666666;
    private int underlineColor = 0x1A000000;
    private int dividerColor = 0x1A000000;
    private boolean shouldExpand = false;
    private boolean textAllCaps = true;
    private int scrollOffset = 52;
    private int indicatorHeight = 8;
    private int underlineHeight = 2;
    private int dividerPadding = 12;
    private int tabPadding = 12;
    private int dividerWidth = 1;
    private int tabTextSize = 15;
    private int tabTextColor = 0xFF666666;
    private int selectedTabTextColor = 0xFF666666;
    private Typeface tabTypeface = null;
    private int tabTypefaceStyle = Typeface.NORMAL;
    private int lastScrollX = 0;
    private int tabBackgroundResId = R.color.color_fcfcfc;
    private Locale locale;

    public PagerSlidingTabStrip (Context context) {
        this (context, null);
    }

    public PagerSlidingTabStrip (Context context, AttributeSet attrs) {
        this (context, attrs, 0);
    }

    public PagerSlidingTabStrip (Context context, AttributeSet attrs, int defStyle) {
        super (context, attrs, defStyle);

        setFillViewport (true);
        setWillNotDraw (false);

        tabsContainer = new LinearLayout (context);
        tabsContainer.setOrientation (LinearLayout.HORIZONTAL);
        tabsContainer.setLayoutParams (new LayoutParams (LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        addView (tabsContainer);

        DisplayMetrics dm = getResources ().getDisplayMetrics ();

        scrollOffset = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm);
        indicatorHeight = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, indicatorHeight, dm);
        underlineHeight = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, underlineHeight, dm);
        dividerPadding = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, dividerPadding, dm);
        tabPadding = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm);
        dividerWidth = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_DIP, dividerWidth, dm);
        tabTextSize = (int) TypedValue.applyDimension (TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm);

        // get system attrs (android:textSize and android:textColor)

        TypedArray a = context.obtainStyledAttributes (attrs, ATTRS);

        tabTextSize = a.getDimensionPixelSize (0, tabTextSize);
        tabTextColor = a.getColor (1, tabTextColor);

        a.recycle ();

        // get custom attrs

        a = context.obtainStyledAttributes (attrs, R.styleable.PagerSlidingTabStrip);

        indicatorColor = a.getColor (R.styleable.PagerSlidingTabStrip_pstsIndicatorColor, indicatorColor);

        //tab文字选中时的颜色,默认和滑动指示器的颜色一致
        selectedTabTextColor = a.getColor (R.styleable.PagerSlidingTabStrip_selectedTabTextColor, indicatorColor);

        underlineColor = a.getColor (R.styleable.PagerSlidingTabStrip_pstsUnderlineColor, underlineColor);
        dividerColor = a.getColor (R.styleable.PagerSlidingTabStrip_pstsDividerColor, dividerColor);
        indicatorHeight = a.getDimensionPixelSize (R.styleable.PagerSlidingTabStrip_pstsIndicatorHeight, indicatorHeight);
        underlineHeight = a.getDimensionPixelSize (R.styleable.PagerSlidingTabStrip_pstsUnderlineHeight, underlineHeight);
        dividerPadding = a.getDimensionPixelSize (R.styleable.PagerSlidingTabStrip_pstsDividerPadding, dividerPadding);
        tabPadding = a.getDimensionPixelSize (R.styleable.PagerSlidingTabStrip_pstsTabPaddingLeftRight, tabPadding);
        tabBackgroundResId = a.getResourceId (R.styleable.PagerSlidingTabStrip_pstsTabBackground, tabBackgroundResId);
        shouldExpand = a.getBoolean (R.styleable.PagerSlidingTabStrip_pstsShouldExpand, shouldExpand);
        scrollOffset = a.getDimensionPixelSize (R.styleable.PagerSlidingTabStrip_pstsScrollOffset, scrollOffset);
        textAllCaps = a.getBoolean (R.styleable.PagerSlidingTabStrip_pstsTextAllCaps, textAllCaps);

        a.recycle ();

        rectPaint = new Paint ();
        rectPaint.setAntiAlias (true);
        rectPaint.setStyle (Style.FILL);

        dividerPaint = new Paint ();
        dividerPaint.setAntiAlias (true);
        dividerPaint.setStrokeWidth (dividerWidth);

        defaultTabLayoutParams = new LinearLayout.LayoutParams (LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
        expandedTabLayoutParams = new LinearLayout.LayoutParams (0, LayoutParams.MATCH_PARENT, 1.0f);

        if (locale == null) {
            locale = getResources ().getConfiguration ().locale;
        }
    }

    public void setViewPager (ViewPager pager) {
        this.pager = pager;

        if (pager.getAdapter () == null) {
            throw new IllegalStateException ("ViewPager does not have adapter instance.");
        }

        pager.setOnPageChangeListener (pageListener);

        notifyDataSetChanged ();
    }

    public void setOnPageChangeListener (OnPageChangeListener listener) {
        this.delegatePageListener = listener;
    }

    public void notifyDataSetChanged () {

        tabsContainer.removeAllViews ();

        tabCount = pager.getAdapter ().getCount ();

        for (int i = 0; i < tabCount; i++) {

            if (pager.getAdapter () instanceof IconTabProvider) {
                addIconTab (i, ((IconTabProvider) pager.getAdapter ()).getPageIconResId (i));
            } else {
                addTextTab (i, pager.getAdapter ().getPageTitle (i).toString ());
            }

        }

        updateTabStyles ();

        getViewTreeObserver ().addOnGlobalLayoutListener (new OnGlobalLayoutListener () {

            @Override
            public void onGlobalLayout () {
                getViewTreeObserver ().removeGlobalOnLayoutListener (this);
                currentPosition = pager.getCurrentItem ();
                scrollToChild (currentPosition, 0);
            }
        });
    }

    public TextView getTabByIndex (int index) {
        if (index >= tabsContainer.getChildCount ()) {
            return null;
        }
        return (TextView) tabsContainer.getChildAt (index);
    }

    private void addTextTab (final int position, String title) {

        TextView tab = new TextView (getContext ());
        tab.setText (title);
        tab.setGravity (Gravity.CENTER);
        tab.setSingleLine ();
        addTab (position, tab);
    }

    private void addIconTab (final int position, int resId) {

        ImageButton tab = new ImageButton (getContext ());
        tab.setImageResource (resId);
        addTab (position, tab);
    }

    private void addTab (final int position, View tab) {
        tab.setFocusable (true);
        tab.setOnClickListener (new OnClickListener () {
            @Override
            public void onClick (View v) {
                pager.setCurrentItem (position);
            }
        });

        tab.setPadding (tabPadding, 0, tabPadding, 0);
        tabsContainer.addView (tab, position, shouldExpand ? expandedTabLayoutParams : defaultTabLayoutParams);
    }

    private void updateTabStyles () {

        for (int i = 0; i < tabCount; i++) {

            View v = tabsContainer.getChildAt (i);

            v.setBackgroundResource (tabBackgroundResId);

            if (v instanceof TextView) {

                TextView tab = (TextView) v;
                tab.setTextSize (TypedValue.COMPLEX_UNIT_PX, tabTextSize);
                tab.setTypeface (tabTypeface, tabTypefaceStyle);
                tab.setTextColor (tabTextColor);

                // setAllCaps() is only available from API 14, so the upper case is made manually if we are on a
                // pre-ICS-build
                if (textAllCaps) {
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                        tab.setAllCaps (true);
                    } else {
                        tab.setText (tab.getText ().toString ().toUpperCase (locale));
                    }
                }
                if (i == selectedPosition) {
                    tab.setTextColor (selectedTabTextColor);
                }
            }
        }

    }

    private void scrollToChild (int position, int offset) {

        if (tabCount == 0) {
            return;
        }

        int newScrollX = tabsContainer.getChildAt (position).getLeft () + offset;

        if (position > 0 || offset > 0) {
            newScrollX -= scrollOffset;
        }

        if (newScrollX != lastScrollX) {
            lastScrollX = newScrollX;
            scrollTo (newScrollX, 0);
        }

    }

    @Override
    protected void onDraw (Canvas canvas) {
        super.onDraw (canvas);

        if (isInEditMode () || tabCount == 0) {
            return;
        }

        final int height = getHeight ();

        // draw underline
        rectPaint.setColor (underlineColor);
        canvas.drawRect (0, height - underlineHeight, tabsContainer.getWidth (), height, rectPaint);

        // draw indicator line
        rectPaint.setColor (indicatorColor);

        // default: line below current tab
        View currentTab = tabsContainer.getChildAt (currentPosition);
        float lineLeft = currentTab.getLeft ();
        float lineRight = currentTab.getRight ();

        // if there is an offset, start interpolating left and right coordinates between current and next tab
        if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {

            View nextTab = tabsContainer.getChildAt (currentPosition + 1);
            final float nextTabLeft = nextTab.getLeft ();
            final float nextTabRight = nextTab.getRight ();

            lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) * lineLeft);
            lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) * lineRight);
        }

        canvas.drawRect (lineLeft, height - indicatorHeight, lineRight, height, rectPaint);

        // draw divider

        dividerPaint.setColor (dividerColor);
        for (int i = 0; i < tabCount - 1; i++) {
            View tab = tabsContainer.getChildAt (i);
            canvas.drawLine (tab.getRight (), dividerPadding, tab.getRight (), height - dividerPadding, dividerPaint);
        }
    }

    public void setIndicatorColorResource (int resId) {
        this.indicatorColor = getResources ().getColor (resId);

        invalidate ();
    }

    public int getIndicatorColor () {
        return this.indicatorColor;
    }

    public void setIndicatorColor (int indicatorColor) {
        this.indicatorColor = indicatorColor;

        invalidate ();
    }

    public int getIndicatorHeight () {
        return indicatorHeight;
    }

    public void setIndicatorHeight (int indicatorLineHeightPx) {
        this.indicatorHeight = indicatorLineHeightPx;
        invalidate ();
    }

    public void setUnderlineColorResource (int resId) {
        this.underlineColor = getResources ().getColor (resId);
        invalidate ();
    }

    public int getUnderlineColor () {
        return underlineColor;
    }

    public void setUnderlineColor (int underlineColor) {
        this.underlineColor = underlineColor;
        invalidate ();
    }

    public void setDividerColorResource (int resId) {
        this.dividerColor = getResources ().getColor (resId);
        invalidate ();
    }

    public int getDividerColor () {
        return dividerColor;
    }

    public void setDividerColor (int dividerColor) {
        this.dividerColor = dividerColor;
        invalidate ();
    }

    public int getUnderlineHeight () {
        return underlineHeight;
    }

    public void setUnderlineHeight (int underlineHeightPx) {
        this.underlineHeight = underlineHeightPx;
        invalidate ();
    }

    public int getDividerPadding () {
        return dividerPadding;
    }

    public void setDividerPadding (int dividerPaddingPx) {
        this.dividerPadding = dividerPaddingPx;
        invalidate ();
    }

    public int getScrollOffset () {
        return scrollOffset;
    }

    public void setScrollOffset (int scrollOffsetPx) {
        this.scrollOffset = scrollOffsetPx;
        invalidate ();
    }

    public boolean getShouldExpand () {
        return shouldExpand;
    }

    public void setShouldExpand (boolean shouldExpand) {
        this.shouldExpand = shouldExpand;
        notifyDataSetChanged ();
    }

    public boolean isTextAllCaps () {
        return textAllCaps;
    }

    public void setAllCaps (boolean textAllCaps) {
        this.textAllCaps = textAllCaps;
    }

    public int getTextSize () {
        return tabTextSize;
    }

    public void setTextSize (int textSizePx) {
        this.tabTextSize = textSizePx;
        updateTabStyles ();
    }

    public void setTextColorResource (int resId) {
        this.tabTextColor = getResources ().getColor (resId);
        updateTabStyles ();
    }

    public int getTextColor () {
        return tabTextColor;
    }

    public void setTextColor (int textColor) {
        this.tabTextColor = textColor;
        updateTabStyles ();
    }

    public void setSelectedTextColorResource (int resId) {
        this.selectedTabTextColor = getResources ().getColor (resId);
        updateTabStyles ();
    }

    public int getSelectedTextColor () {
        return selectedTabTextColor;
    }

    public void setSelectedTextColor (int textColor) {
        this.selectedTabTextColor = textColor;
        updateTabStyles ();
    }

    public void setTypeface (Typeface typeface, int style) {
        this.tabTypeface = typeface;
        this.tabTypefaceStyle = style;
        updateTabStyles ();
    }

    public int getTabBackground () {
        return tabBackgroundResId;
    }

    public void setTabBackground (int resId) {
        this.tabBackgroundResId = resId;
        updateTabStyles ();
    }

    public int getTabPaddingLeftRight () {
        return tabPadding;
    }

    public void setTabPaddingLeftRight (int paddingPx) {
        this.tabPadding = paddingPx;
        updateTabStyles ();
    }

    @Override
    public void onRestoreInstanceState (Parcelable state) {
        SavedState savedState = (SavedState) state;
        super.onRestoreInstanceState (savedState.getSuperState ());
        currentPosition = savedState.currentPosition;
        requestLayout ();
    }

    @Override
    public Parcelable onSaveInstanceState () {
        Parcelable superState = super.onSaveInstanceState ();
        SavedState savedState = new SavedState (superState);
        savedState.currentPosition = currentPosition;
        return savedState;
    }

    public interface IconTabProvider {
        int getPageIconResId (int position);
    }

    static class SavedState extends BaseSavedState {
        public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState> () {

            @Override
            public SavedState createFromParcel (Parcel in) {
                return new SavedState (in);
            }

            @Override
            public SavedState[] newArray (int size) {
                return new SavedState[size];
            }
        };
        int currentPosition;

        public SavedState (Parcelable superState) {
            super (superState);
        }

        private SavedState (Parcel in) {
            super (in);
            currentPosition = in.readInt ();
        }

        @Override
        public void writeToParcel (Parcel dest, int flags) {
            super.writeToParcel (dest, flags);
            dest.writeInt (currentPosition);
        }
    }

    private class PageListener implements OnPageChangeListener {

        @Override
        public void onPageScrolled (int position, float positionOffset, int positionOffsetPixels) {
            currentPosition = position;
            currentPositionOffset = positionOffset;

            scrollToChild (position, (int) (positionOffset * tabsContainer.getChildAt (position).getWidth ()));

            invalidate ();

            if (delegatePageListener != null) {
                delegatePageListener.onPageScrolled (position, positionOffset, positionOffsetPixels);
            }
        }

        @Override
        public void onPageSelected (int position) {
            selectedPosition = position;
            updateTabStyles ();
            if (delegatePageListener != null) {
                delegatePageListener.onPageSelected (position);
            }
        }

        @Override
        public void onPageScrollStateChanged (int state) {
            if (state == ViewPager.SCROLL_STATE_IDLE) {
                scrollToChild (pager.getCurrentItem (), 0);
            }

            if (delegatePageListener != null) {
                delegatePageListener.onPageScrollStateChanged (state);
            }
        }
    }
}